An increasing number of abdominal surgical procedures are being performed with laparoscopic techniques in order to avoid a large skin incision. Typically in laparoscopic surgery, a special needle, similar to the pneumoneedles described in U.S. Pat. No. 4,808,168 to Warring and U.S. patent application Ser. No. 07/808,152 (both of which are herein expressly incorporated by reference), is inserted through the skin, and used to inflate the abdominal cavity with an insufflating gas such as CO.sub.2. Once the abdomen is adequately dilated, the needle is removed and a rigid cannula with an access tube with a larger diameter (for example 5, 10 or 11 mm) is passed through the skin in the same location.
The access tube provides access for laparoscopes or other laparoscopic surgical tools such as the stapler described in U.S. Pat. No. 5,040,715 or the surgical clip appliers described in U.S. Pat. No.'s 5,084,057 and 5,100,420. To drive the access tube through the skin, the surgeon places a trocar obturator in the lumen of the access tube to provide a sharp, leading edge for cutting tissue. Often several trocar and cannula assemblies are used during a laparoscopic surgical procedure on the same patient.
The art is replete with trocar and cannula devices. Diverse designs for trocar and cannula assemblies exist. Trocars may be constructed (1) to include a mechanism for protecting underlying organs from sharp obturator surfaces, (2) to be reusable on multiple patients, or (3) to be disposable to minimize sterilization and sharpness issues present with reusable trocars. Cannulae may be constructed (1) to include several different features to restrict loss of insufflating gas from the abdominal cavity or to afford replenishment of the insufflating gas within the abdominal cavity, (2) to be disposable, (3) to be reusable, or (4) for specialty applications such as extended length for obese patients or with specialized electrical properties for use with laparoscopic instruments. Additionally, as surgeons gain experience with laparoscopic surgical procedures, they are developing preferences for customized surgical devices, including trocar and cannula assemblies.
Further, cost considerations are becoming increasingly important in the determination of which cannula and trocar assemblies are used during a laparoscopic surgical procedure. For example, a trocar assembly having a mechanism for protecting underlying organs from a sharp obturator tip is typically a complex and expensive device relative to a trocar assembly without such a mechanism.
U.S. Pat. No. 5,144,942 discloses an endoscopic or laparoscopic instrumentation kit comprising a plurality of trocar assemblies and cannula assemblies. The trocar assemblies may comprise different sized (e.g. 5 mm and 10 mm diameters) trocars and the cannula assemblies may comprise different sized cannulae (e.g. 5 mm and 10 mm diameters). However, such packages encounter problems when a surgeon would prefer to take advantage of the features of different types of trocars and different types of cannula.